Irrigation system and volume control valve therefor

Abstract

The disclosure is directed to a center pivot irrigation system capable of operation under high or low water pressure and a constant volume sprinkler head therefor, which together provide uniform water distribution over an agricultural field notwithstanding the presence of hills and valleys in the field, pressure fluctuations of the water source, friction losses or the direction or magnitude of the wind. The system employs a plurality of sprinkler heads each of which provides a constant volume of water to the annular area over which it travels. Because the annular areas increase in size and total water requirements with increasing distance from the center pivot, the water delivering capacity of each sprinkler head is chosen as a direct function of its radial distance from the center pivot, thus insuring the same water distribution to all points on the field. Each sprinkler head is designed to produce a spray pattern that extends laterally outward with a predetermined directional orientation. A vertical tail or rudder associated with the sprinkler head acts in weather vane fashion to direct the directional spray pattern into the wind at all times, thus preventing the water spray from being blown from its intended area, which results in nonuniform distribution. The sprinkler heads are also constructed for tipping relative to a vertical axis, and ailerons extending laterally from the rudder act to tip the head and spray pattern downward to a degree in the face of particularly strong winds, thus insuring that the water reaches its destination.

What is claimed is: 
     
       1. A device for distributing a constant volume spray of water comprising: (a) an enclosed housing defining an internal chamber, a fluid inlet adapted for connection to a source of water for receiving water into the chamber, and an outlet constructed and arranged to issue a jet of water therefrom, the transverse dimension of the internal chamber being large in comparison with the transverse dimension of the inlet and outlet;   (b) spray deflector means disposed relative to the outlet for intercepting the jet of water and deflecting it into a spray pattern of predetermined shape;   (c) volume control means associated with the housing outlet for providing an essentially constant output volume of water from the housing outlet; and   
     
     
       (d) a wall member projecting internally into the chamber from the housing outlet in encircling relation thereto and in general alignment therewith, the wall chamber defining an open free end through which water is received from the inlet, said wall member at its free end having an internal transverse dimension larger than the transverse dimension of said inlet and outlet, and said wall member being spaced from the internal wall of the housing to define a dead ended annular space therewith in which air may be caught to act as a shock absorbing cushion to incoming water. 
     
     
       2. The device defined by claim 1, wherein the wall member is cylindrical in shape. 
     
     
       3. The device defined by claim 2, which further comprises a screen member disposed over the free end of the cylindrical member. 
     
     
       4. The device defined by claim 3, wherein the screen member is conical in shape, the concave side thereof facing the housing inlet. 
     
     
       5. The device defined by claim 1, which further comprises a screen member disposed over the free end of the wall member. 
     
     
       6. The device defined by claim 1, wherein the outlet is defined by a nozzle member projecting through an opening in the housing and retainably disposed within the wall member. 
     
     
       7. The device defined by claim 6, wherein the nozzle member is removably disposed in the housing opening to permit interchangeability thereof. 
     
     
       8. The device defined by claim 7, wherein the housing inlet and outlet are alignably disposed in different housing sections. 
     
     
       9. The device defined by claim 1, wherein the enclosed housing comprises two interchangeable, matable sections. 
     
     
       10. The device defined by claim 1, wherein the wall member is disposed in alignment with the housing inlet. 
     
     
       11. The device defined by claim 1, wherein the enclosed housing is substantially bowl shaped, and the side wall of the internal chamber extends smoothly and continuously from the fluid inlet to the dead ended chamber. 
     
     
       12. A device for distributing a constant volume spray of water comprising: (a) an enclosed housing defining an internal chamber, a fluid inlet adapted for connection to a source of water for receiving water into the chamber, and an outlet constructed and arranged to issue a jet of water therefrom, the transverse dimension of the internal chamber being large in comparison with the transverse dimension of the inlet and outlet; (b) a cylindrical member projecting internally into the chamber from the housing outlet and in general alignment therewith, the cylindrical member defining an open free end through which water is received from the inlet, said cylindrical member at its free end having an internal transverse dimension larger than the transverse dimension of said inlet and outlet, the side wall of the cylindrical member being spaced from the internal wall of the housing to define a dead ended annular space therewith in which air may be caught to act as a shock absorbing cushion to incoming water;   (c) spray deflector means disposed relative to the housing outlet for intercepting the jet of water and deflecting it into a spray pattern of predetermined shape;   (d) and volume control means for providing an essentially constant output volume of water from the housing outlet, comprising a resilient washer retainably disposed within the cylindrical member and having a control opening disposed in alignment with the housing outlet, the resilient washer having a normal unstressed state in which the control opening permits the flow of a maximum amount of water, and a flow of stress states in which the control opening becomes progressively restrictive, the resilient washer being disposed within the cylindrical member so that incoming water acts on and stresses the washer as a function of water pressure.   
     
     
       13. The device defined by claim 12, wherein the housing comprises a control surface with which the outlet side of the resilient washer cooperates. 
     
     
       14. The device defined by claim 13, which further comprises auxiliary flow means for normally spacing the outlet side of the resilient washer from the control surface and from the cylindrical member to permit an auxiliary flow thereby when the resilient washer is not fully stressed. 
     
     
       15. The apparatus defined by claim 14, wherein the spacing means comprises a plurality of leg members integrally formed on the peripheral side of the resilient washer and extending beyond its outlet side, the ends of the leg members engaging the control surface and deformable with increasing water pressure to permit controlled engagement of the outlet side of the resilient washer with the control surface to progressively decrease said auxiliary flow. 
     
     
       16. The device defined by claim 14, wherein said control surface is formed within the cylindrical member in encircling relationship to the outlet, and the auxiliary flow means comprises a plurality of auxiliary flow channels formed on the inner cylindrical surface of the cylindrical member and extending radially inward on the control surface, the grooves being disposed relative to the resilient washer whereby, in its unstressed state, the washer permits auxiliary flow to the outlet, and with increasing water pressure, the washer becomes more stressed and progressively restricts the auxiliary flow channels. 
     
     
       17. The device defined by claim 16, wherein the cylindrical member is separate from the housing and interchangeably constructed. 
     
     
       18. The device defined by claim 17, wherein the cylindrical member comprises a nozzle member that cooperates with the housing to define said outlet. 
     
     
       19. The device defined by claim 16, wherein the auxiliary flow channels are equiangularly disposed within the cylindrical member. 
     
     
       20. The device defined by claim 16, wherein the auxiliary flow channels are generally semicircular in cross section. 
     
     
       21. The device defined by claim 16, wherein the circumferential width of each auxiliary flow channel is significantly greater than its radial depth. 
     
     
       22. The device defined by claim 16, wherein each auxiliary flow channel terminates in a blind end within the control surface, said blind end being spaced from the outlet, whereby engagement of the resilient washer with the control surface progressively restricts and ultimately terminates auxiliary flow. 
     
     
       23. The device defined in claim 12, wherein the resilient washer is normally concavo-convex and is stressable toward a flattened state. 
     
     
       24. The device defined by claim 12, wherein the cylindrical member is disposed in alignment with the housing inlet. 
     
     
       25. The device defined by claim 12, wherein a screen member is disposed over the free end of the cylindrical member. 
     
     
       26. The device defined by claim 25, wherein the screen member is conical in shape, the concave side thereof facing the housing inlet to uniformly distribute water over the inlet face of the resilient washer. 
     
     
       27. The device defined by claim 12, wherein the resilient washer is removably retained within the enclosure to permit interchangeability thereof. 
     
     
       28. The device defined by claim 12, wherein the resilient washer in its unstressed state defines a conical surface facing the housing outlet, the resilient washer being stressable by water pressure so that the conical surface approaches flatness. 
     
     
       29. The device defined by claim 12, wherein the control opening of the resilient washer is smaller than the housing outlet. 
     
     
       30. The device defined by claim 12, wherein said control surface is substantially flat, and the resilient washer defines a peripheral region that normally contacts said flat control surface in sealing relation, and increasingly engages the flat surface as it is stressed to its flattened state. 
     
     
       31. The device defined by claim 12, wherein the enclosed housing is substantially bowl shaped, and the side wall of the internal chamber extends smoothly and continuously from the fluid inlet to the dead ended chamber. 
     
     
       32. A spray head for distributing a constant volume of water comprising: (a) an enclosed housing defining an internal chamber, said housing being comprised of a lower section having an inlet formed through it for receiving water into the chamber and an upper section removably secured to the lower section, said upper section having an outlet formed through it in alignment with said inlet to issue a jet of water therefrom;   (b) spray deflector means disposed relative to the outlet for intercepting the jet of water and deflecting it into a spray pattern of predetermined shape;   
     
     
       (c) a wall member formed integral with the upper section of the housing and projecting internally into the chamber from the housing outlet in an encircling relation thereto and in general alignment therewith, the wall member defining an open free end through which water is received from the inlet; and (d) volume control means for providing an essentially constant output volume of water from the housing outlet, comprising a resilient washer retainably disposed within the wall member and having a control opening disposed adjacent to and in alignment with the housing outlet, the resilient washer having a normal unstressed state in which the control opening permits the flow of a maximum volume of water, and a flow of stress states in which the control opening becoming progressively restrictive, the resilient washer being disposed within the wall member so that incoming water acts on and stresses the washer as a function of water pressure, said wall member extending from said resilient washer toward said inlet a distance several times greater than the thickness of said resilient washer whereby the internal surface of said wall member serves to guide incoming water to said resilient washer and said outlet.